Some amount of bleeding is invariably associated with surgical procedures. The released blood obscures the surgeon's view by accumulating over the surgical site. In order to maintain clear vision the surgeon or an assistant intermittently aspirates the clotted and unclotted blood from the surgical site.
The prior art surgical aspiration systems generally comprise a vacuum source connected to an aspiration cannula via a suction tube. The surgeon or an assistant, while holding the aspiration cannula in one hand, bring the tip of the aspiration cannula in close proximity to the surgical site and by virtue of a negative pressure present in the suction tube the unclotted blood and the irrigation fluid is aspirated via the tip of the aspiration cannula. However, blood clots and tissue debris may block tip or the lumen of the aspiration cannula and in order to continue aspiration the surgeon attempts to dislodge the blockage by vigorously shaking the aspiration cannula. If this does not work, the suction tube is temporarily disconnected and the aspiration cannula is again shaken vigorously. If this also does not work, the surgeon mechanically dislodges the clot from the tip of the aspiration cannula by applying traction with his other free or freed hand. If the clot blocks the lumen of the aspiration cannula in a permanent like manner, then the surgeon has no choice but to detach the suction tube from the aspiration cannula and to flush the aspiration cannula in a retrograde manner under high pressure using a hypodermic syringe. Thus, the prior art surgical aspiration systems are not single handed systems because the surgeon frequently has to use his other hand in order to dislodge or to flush out the blood clots from the blocked aspiration cannula. The prior art aspiration systems also cannot function in an uninterrupted manner, because the blood clots and tissue debris which keep on blocking the tip or the lumen of the aspiration cannula have to be first dislodged or flushed before aspiration can be again resumed. The uncontrolled negative pressure created in the prior art systems can accidentally traumatize vital structures like nerves and blood vessels over the brain surface.
The present invention overcomes the disadvantages of the surgical aspirating systems of the prior art by providing a system and method for surgical aspiration which is single handed, uninterrupted, more efficient and safer than the prior art systems.
The problems associated with the existing “surgical aspiration systems” and the advantages offered by the proposed system shall now be discussed in detail in context with neurosurgical procedures like brain surgery.
BRAIN SURGERY: The brain is a very delicate organ and contains many small vital nerves and blood vessels. In brain surgery, homeostasis is mainly achieved via bipolar coagulation but even this is used very sparingly due to the fear of traumatizing vital nerves and blood vessels which could disrupt the sensory or motor functions to a vital organ. Due to extremely judicious and minimal homeostasis, brain surgery is associated with relatively more bleeding in comparison to other open surgeries. It is extremely important to maintain a constant clear vision of the brain structures and the same is achieved by a meticulously and almost continuous aspiration throughout a brain surgery procedure. In brain surgery, a lot of surgical time is wasted on account of an inefficient surgical aspiration. The aspiration related problems in brain surgery are discussed individually as follows:
Blockage of the cannula lumen: The brain is a delicate organ. Thus, neurosurgeons prefer to use miniature aspiration cannulas having inner diameters ranging between 0.3 to 3 mm. Due to the small lumen diameter, the lumen of these miniature cannulas gets easily blocked by blood clots and tissue debris. Such obstruction is permanent in nature and is relieved by disconnecting the suction tube from the cannula and then flushing the aspiration cannula retrogradely by a hypodermic surgical syringe. Many neurosurgeons like to hold the bipolar forceps in their right hand and the aspiration cannula in their left hand. In the case of a permanent like blockage of the cannula lumen, as described, the surgeon hands over the aspiration cannula to an assistant who in turn disconnects the suction tube and flushes the aspiration cannula. This wastes valuable surgical time and additional clots are also formed during this time which also need to be removed from the operative site. In the system of the proposed invention, the clot which blocks the aspiration cannula in a permanent like manner is flushed automatically with a desired time lag and the surgeon never has to hand over the cannula to an assistant for flushing. In the present invention, the clots are flushed out after a predictably desired time lag period during which time the surgeon has the option to move the tip of the cannula to a location outside the surgical field such that the blood clots are ultimately disposed well outside the operative field.
Blockage of the cannula tip: Clots also frequently superficially block only the tip and not the lumen of the aspiration cannula. In such situations, the surgeon manually dislodges the clot with his other free or freed hand which again makes surgical aspiration during brain surgery a double handed process. However, with the system of the present invention, the blood clots which superficially block the tip of the aspiration cannula do not have to be mechanically dislodged by using the other free or freed hand because such clots automatically fall away from the tip of the cannula after a predictably desired time interval during which time the surgeon again has time to move the cannula tip outside the surgical field such that the unwanted clots are disposed outside the surgical field. Such feature of the present invention not only makes surgical aspiration as a single handed maneuver but it also allows an almost uninterrupted aspiration, all of which ultimately translates into an enhanced surgical efficiency, an enhanced patient safety and a decrease in the total operating time.
Accidental trauma to brain structures: The prior art surgical aspiration systems often create uncontrolled negative pressures. In case the tip of the aspiration cannula accidentally touches a nerve or a small blood vessel, such structures may be accidentally damaged which may lead to an irreversible motor or sensory loss to important organs like the hand or leg. The present invention minimizes such accidental trauma.
The present invention has a critically vital role in brain surgery. However, the invention also finds important use in laparoscopic surgery which is described in the next paragraph.
LAPAROSCOPIC SURGERY: In operative laparoscopic procedures, blood invariably oozes from the operative site. Thus, the operative field is intermittently washed by irrigating with normal saline. However, some quantity of blood organizes in the form of clots. The irrigating fluid tends to accumulate in the dependent recesses of the posterior abdominal wall inside the inflated abdominal cavity. Such bloody irrigation fluid mixed with clots needs to be intermittently aspirated in order to maintain a clear operating field. However, the blood clots floating in the accumulated bloody irrigation fluid tend to block the tip of the aspiration cannula, and in order to relieve such blocks the surgeon either momentarily detaches the suction tube from the aspiration cannula or the surgeon vigorously shakes the tip of the aspiration cannula in order to dislodge the clot. All these maneuvers increase surgical time and can also cause surgical trauma. In brain surgery as described above and in other open surgical procedures the surgeon can use his/her other free or freed hand to dislodge a clot from the tip of the aspiration cannula, however even if the surgeon wishes, the same is not possible in laparoscopic surgery because the tip of the aspiration cannula is always located inside the distended abdominal cavity, a site which is inaccessible to the hand. In case the blood clot tends to block the lumen of the aspiration cannula in permanent like manner, then the aspiration cannula needs to be flushed as described in the previous paragraphs. The system of the present invention, when used with laparoscopic surgery, automatically flushes and also dislodges clots which intermittently block the aspiration cannula. Thus, the present invention makes surgical aspiration in laparoscopic surgery a single handed and uninterrupted process. As in brain surgery and in other open surgical procedures, in laparoscopic surgery it is not possible to dispose the non aspirated clots and other necrotic material completely outside the surgical field; at best, it is possible to temporarily park the blood clots and necrotic material from on site to another site over the posterior abdominal wall inside the inflated abdominal cavity and the present invention aids in such a maneuver as well.
Besides brain surgery and laparoscopic surgery, the present invention is useful in many other open surgical procedures as well. The use of the present invention in Caesarian Section surgery, a gynecological procedure, shall be briefly described.
CAESARIAN SECTION: In a Caesarian Section, the lower uterine body is cut with a sharp knife in order to extract the baby from the uterine cavity. Subsequent to cutting the uterine wall, a substantially large volume of amniotic fluid contained inside the fetal sac starts escaping through the uterine wall and a substantial quantity of blood which is invariably released from cut uterine wall forms large clots which tend to float in the amniotic fluid. In a Caesarian Section, the obstetrician is always in a hurry to extract the baby because any delay may cause harm to the baby and also to the mother. In order to maintain a clear operating field, the obstetrician immediately starts aspirating the blood tinged amniotic fluid but such aspiration is repeatedly interrupted by large clots which block the aspiration cannula and this may increase the time taken to extract the baby. The system of the present invention, by providing a single handed almost uninterrupted aspiration of the amniotic fluid and blood, can enhance the surgical safety for the baby as well as the mother.
The present invention also enhances the patient's safety and the surgical efficiency in extensive cancer surgeries, which are associated with substantial bleeding and in which tissue released as a result of extensive debridement needs to be removed from the surgical site.